Electric dry shaver formed of coaxial assemblies



0d. 1, 1963 MINEHARU OMORI ET AL 3,403,440

ELECTRIC DRY SHAVER FORMED OF COAXIAL ASSEMBLIES Filed on. 12, 1966 2 Sheets-Sheet 1 EGG SB Och 1968 MINIEHARU OMORI ET AL 3,403,440

ELECTRIC DRY SHAVER FORMED OF COAXIAL ASSEMBLIES Filed Oct. 12, 1966 2 Sheets-Sheet 2 n11 NE-KS m-mu X l Juana Hana loan United States Patent 3,403,440 ELECTRIC DRY SHAVER FORMED OF COAXIAL ASSEMBLIES Mineharu Omori and Shozo Matsubara, Ibaraki-shi,

Osaka-fu, Tadayoshi Nakamura, Kadoma-shi, Osakafu, and Seiji Harada, Suita-shi, Osaka-fu, Japan, assignors to Hitachi Maxell Ltd., Osaka-Eu, Japan, a corporation of Japan Filed Oct. 12, 1966, Ser. No. 586,091 Claims priority, application Japan, Oct. 29, 1965, 40/88,265; Nov. 6, 1965, 40/90,252 9 Claims. (Cl. 30--43.6)

ABSTRACT OF THE DISCLOSURE An electric dry shaver consisting of a plurality of cylindrical assemblies coupled together by threaded engagements along a common axis.

The present invention relates in general to shaving devices, and more particularly, to an electric dry shaver which is completely portable, carrying its own self-contained power supply.

Electric dry shavers which have been in past use, either of the portable type or the type requiring an external power supply, generally have a casing consisting of a pair of half-shells which are fastened together by suitable securing means to enclose the various operating components of the shaving device. These casing half-shells are popularly constructed of a plastic or synthetic material and are provided with structural partitioning at the interior surfaces thereof for properly supporting the various operating components of the shaver, which are wired one to the other in the interior of the casing.

However, the known shavers as described above, and especially the portable shavers which are extremely suitable for travel purposes, have several drawbacks relating to their overall construction. One problem results from the fact that the casing is made from a plastic or readily destructible material which is unable to withstand the shock of travel and must therefore be carried in a protective carrying case of rigid construction for protection against damage to the shaver parts. In addition, should these shavers be dropped on a hard surface, internal parts of the shaver may be broken in addition to the casing itself as a result of the weak casing construction utilized. However, in spite of the known drawbacks in utilizing a plastic casing for electric dry shavers, it has been recognized. by the industry that the manufacture of the presently used shaver casings of a more nondestructible material materially increases the weight of the shaver, due to the large size of the casing provided, thereby making it undesirable to the user from the standpoint of ease of manipulation and fatigue.

A second difiiculty encountered in present day dry shavers relates to the substantially permanent construction of such shavers. In the shaving units presently available, the working parts of the shaver are secured within the half-shells of the casing by minute screws and other fastening devices which render the simple dismantling of the shaver rather difiicult by those not particularly skilled or mechanically inclined. Thus, as a regular routine from time to time it is necessary to bring the shaver to a specialist for cleaning or repair, which results in periodic costs of a substantial nature in comparison to the original cost of the shaver. In addition, the hand wiring between the various working components of the shaver increases the manufacturing cost of the shaver and also results in increased costs of repair, should such become necessary.

In avoiding the above-mentioned difficulties, the present invention provides an electric dry shaver of the type 3,403,440 Patented Oct. 1, 1968 provided with a guard having a plurality of perforations and a cutting blade which is pressed elastically against the perforated guard and which is capable of being driven in rotation by an electric motor. In accordance with theinvention, the shaver is provided with its own self-contained removable power supply in the form of a standard dry cell battery and is provided of such construction as to greatly facilitate the disassembly of the shaver even by those having little mechanical skill or aptitude.

Thus, an important feature of the present invention relates to the shaver construction consisting of four major shaver portions or assemblies secured together by threaded engagement thereby greatly simplifying disassembly of the shaver device and reducing the difliculties of repair to a simplified replacement of one of the four basic parts of the device.

It is another basic feature of the present invention to provide a shaver construction wherein internal wiring between the active elements of the shaver is entirely eliminated by providing a metal casing for the shaver which serves as a means of electrical interconnection between the power supply and the shaver motor. The provision of a conductive metal casing for the shaver not only provides for the elimination of the electrical wiring normally utilized in such devices, but also provides a rigid nondestructible protective cover for the operating members of the shaver, thereby eliminating any need for a further protective casing.

Another important feature of the present invention resides in a particularly suitable and convenient switch arrangement for electrically interconnecting the selfcontained power source with the shaver motor via the electrically conductive shaver casing, which switch arrangement is provided as a self-contained unit removable from the shaver device and includes an indicating arrangement for visually determining the active and nonactive positions of the switch.

Another extremely important feature of the present invention is derived from the particular sectional construction of the device in accordance with the invention such that proper lineal arrangement of the various elements of the shaver device along the axis thereof is achieved making possible an extremely accurate positioning of the components with respect to one another and particularly a proper positioning of the cutting blade against the perforated guard so as to provide extremely efficient ope-ration by the cutting head.

A primary object of the present invention is to provide an electric dry shaver capable of eliminating or otherwise materially avoiding the above mentioned drawbacks inherent in known devices of a similar nature.

It is another object of the present invention to gain high accuracy in the position of the cutting blade against the perforated guard by relatively simple means.

It is another object of the present invention to provide a shaver case capable of firm support of the operating elements of the shaver, including the motor, and to remove previously experienced difiiculties in component positioning and support within the shaver casing through the relaxation of the fitting portion.

A further object of the present invention is to provide an electric dry shaver capable of simplified assembly and disassembly and to facilitate the cleaning and repair there-- of through elimination of interior electrical wiring and provision of sectioned components capable of simple replacement.

Still another object of the invention is to provide an electric dry shaver which is easily operated, simple, attractive in appearance and easily repaired and maintained in use.

It is still another object of the present invention to provide an electric dry shaver having a selfcontained power supply which provides a rigid substantially nondestructible casing of light weight and is specifically designed for long eflicient and simplified use.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description thereof when taken in conjunction with the accompanying drawing, which illustrate one embodiment of the present invention, and wherein:

FIGURE 1 is a vertical sectional view of an electric dry shaver in accordance with the present invention;

FIGURE 2 is a bottom plan view of the shaver illustrated in FIGURE 1;

FIGURE 3 is a top plan view of a cutting blade of the type utilized in accordance with the present invention;

FIGURE 4 is a vertical sectional view of an individual removable assembly of the shaver in accordance with the present invention including the electrical motor thereof; and

FIGURE 5 is a sectional view of the dry shaver of the present invention taken along line 5-5 of FIGURE 1.

Referring now to the drawings, wherein like elements have been identified by similar numeral designations throughout the various views, and particularly to FIG- URE 1; a cylindrical shaver case 11 made of a rigid electrically conductive material, such as aluminum or a similar lightweight metal material, serves as the main body portion of the shaver. This case 11 is preferably made of aluminum due to the lightweight substantially nondestructive properties of this metal and its ability to maintain an attractive, tarnish-free appearance provided by the layer of aluminum oxide formed on the outer surface thereof. On an inner wall of the shaver case 11 there is fixed an insulating tube 12 of a plastic or other electrically nonconductive material, which tube 12 is dimensioned to accommodate and properly position along the axis of the case 11 a self-contained power supply for the shaver in the form of a standard dry cell battery 13. The type and rating of the battery 13 is of course determined by the requirements of the shaver motor; however, for purposes of providing a compact and lightweight shaver arrangement providing suflicient power to properly perform the shaving operation in an eflicient manner it is preferred that the standard 1.5 volt alkaline manganese battery or equivalent battery be provided in combination with an electric motor suitably powered thereby.

A second self-contained portion of the electrical shaver in accordance with the present invention is a motor assembly 14 including a cylindrical plastic casing 15 having an outside diameter substantially conforming to the inside diameter of the case 11 of the shaver. On the outer side wall of the plastic casing 15, there is provided an external screw thread 16 which cooperates with threads on the internal surface of the case 11 to provide a threaded engagement between the case 11 and the motor assembly 14. The casing 15 of the motor assembly 14 has a flange 18 dividing the screw thread into two portions for the purpose of providing a limit to determine the proper positioning of the motor assembly 14 in the shaver case 11. Thus, the flange 18 provides a guide which insures the consistently accurate positioning of the motor assembly 14 with respect to the shaver case 11.

The motor assembly 14, which will be described in greater detail hereinafter in connection with FIGURE 4, includes an extending connecting rod 44 powered by the motor within the assembly upon which is slidably mounted a cutting blade 45 which is pressed by means of a coil spring 46 into resilient engagement with a perforated guard 38 made of a thin steel disc and forming part of a third major assembly of the shaver. The guard assembly of the shaver consists of a tubular shell 39 of generally frustoconical shape having a threaded portion 41 for cooperation with an extending threaded portion 42 on the motor assembly 14 above the guide flange 18. The

tubular shell 39 may therefore be secured to the motor assembly 14 by threaded engagement between the threads 41 and 42 with the guide flange 18 serving as a means of accurately positioning this tubular shell 39 with respect to the motor assembly 14. Thus, as a result of the flange 18 the tubular shell 39 is accurately positioned by the same flange with respect to the shaver case 11. The tubular shell 39 carries the thin steel disc serving as the perforated guard 38, which is held at the upper opening of the tubular shell by a locking ring 40, dimensioned to provide a locking engagement between the guard 38 and the tubular shell 39.

The fourth and final assembly portion of the shaver consists of a bottom cap 51 containing a rotary switch for effecting electrical interconnection between the battery 13 and the motor in the assembly 14 via the electrically conducting case 11. The cap 51 containing the rotary switch 50 is made from a plastic material and is provided at the outer surface of the upwardly extending portion 52 thereof with an external thread capable of engaging with an internal thread at the inner surface of the lower portion of the case 11 to thereby provide threaded engagement between the lower switch assembly and the shaver case 11. The bot-tom cap 51 is a plastic frame consisting of a cylindrical wall 52 and an inner web 53 in the center of which is inserted a connecting shaft 54. On the outer end of the connecting shaft 54 is fixed a rotary disc 55 having a knob 56 and an aperture 57. On the inner end of the connecting shaft 54 there is fixed a rotary square plate 58 having an electrically conductive contact segment 59 on one side thereof. A conductive plate 60 placed on the inner surface of the web 53 includes springy elements 61 and also includes a springy conductor 62 maintaining electrical contact with the conductive shaver case 11. A top contact 63 is formed integrally with the contact segment 59 and is provided in firm electrical contact with a metal conducting plate 64 secured by suitable fastening means on an inner step of the plastic cap 50 so that electrical contact is maintained at all times between the plate 64 and the contact 63. A conductive helical spring 65 is positioned upon the metal disc 64 and presses against the negative pole of the battery 13 to force the battery in the direction of the motor assembly 14. As a result, the positive pole of the battery 13 is maintained in firm electrical contact with the positive plate 32 of the motor assembly 14 and forceful electrical contact between the plate 64 and the contact 63 is also assured as a result of this combination.

The contact segment 59 coming into contact with the springy element 61 by the rotation of the rotary disc 55 results in electrical connection from the motor assembly 14 via the positive plate 32 through the battery 13, helical spring 65, conducting plate 64, contact 63, contact segment 59, springy elements 61, conductive plate 60, springy conductor 62, shaver case 11 and springy contact 33 connected to the lower end of the motor assembly 14 forming the negative terminal thereof. Thus, rotation of the disc 55 serves to effect engagement and disengagement of the contact segment 59 with the springy segment 61 of the conductive plate 60 thereby providing for electrical connection and disconnection of the battery 13 from the motor assembly 14.

As a result of the square configuration of the plate 58, and due to the elastically pressed springy elements 61 in firm contact with the sides of the rotary plate 58, the rotary disc 55 is able to remain in only four equilibrium positions separated by degrees of rotation. There are thus two distinct equilibrium positions of the rotary disc 55 wherein the motor is energized and two distinct equilibrium positions where the motor is deenergized. This is due to the fact that a segment 59 in contact with the bat tery through contact 63, plate 64 and spring 65 is located on only one side of the square plate 58 and will thus be connected to the conducting plate 60 only in the two positions of the square plate wherein the springy elements 61 are engaged.

In order to provide visual indication of the postiion or status of the switch element, the underside of the 'web 53 facing the rotary disc 55 is divided into four equal arcs, as shown in dotted line in FIGURE 2 with oppositely disposed quadrants being provided with a common color so that the color visible through the aperture 57 in the rotary disc 55 provides a visual indication of the engaged or disengaged condition of the switch assembly.

Turning now to FIGURE 3, the cutting blade 45 used with the shaver in accordance with the present invention consists of a supporting plate 47 having three wings offset from the main body portion of the plate 47, as illustrated in FIGURE 1. A blade element 49 of substantially elongated U-shaped construction is provided on each of the three wings of the supporting plate 47 and is loosely fastened to each of the respective wings by means of stoppers 48. As a result of the relatively loose fastening of the blade elements to the wings of the supporting plate 47 by the stoppers 48 in conjunction with the coil spring 46 bearing between a collar on the connecting rod 44 and the lower surface of the supporting plate 47, the blade elements 49 are always pressed elastically against the inner face of the guard 38 providing for a uniform sweeping motion of the blade elements across the inner surface of the perforated guard 38 providing continuous uniform contact therewith.

The detailed construction of the motor assembly 14 is illustrated in FIGURE 4. A rotary core 19 carrying a wound coil 20 and a commutator 21 connected to the coil 20 in the well-known manner are fixed to a motor shaft 22, which is supported by a bearing 23 mounted in a suitable bearing surface on a webbed portion of the plastic casing of the motor assembly 14. In a like manner, a bearing 24 fitted on a plastic bracket 25 at the lower end of the casing 15 rides in a suitable bearing surface therein and is secured to the lower end of the motor shaft 22. A metal plate 35 is fixed to the casing 15 by means of rivets 36 and 37, elastically presses the bearing 23 against the casing 15 to provide for proper positioning of the motor within the casing 15. A rivet 30 fastens a positive plate 32 into contact with the lower end of the motor shaft 22 and a rivet 31 fastens a negative plate 33 into constant electrical contact with the casing 11. The rivets 30 and 31 also serve to secure flat springs 26 and 27 having respective brushes 28 and 29 maintained in contact with the commutator 21 on opposite sides thereof thereby providing the means for applying the electrical energy from the power supply 13 to the motor. A cylindrical magnet 34 is held on the inner wall of the casing 15 opposite to the rotary core 19 and serves in the well known manner for providing a field to interact with the field generated by the coils on the rotor portion of the motor.

As is stated above, the tubular shell 39 carrying the perforated guard plate is directly screwed to the outer wall of the projecting top portion 43 of the casing 15. Therefore, in accordance with the present invention, it is possible to gain in a relatively simple manner high accuracy of position of the cutting blade 45 against the guard 38. The motor assembly 14 can be fitted to the shaver case 11 firmly in an easy manner by screwing the casing 15 of the motor 14 to the upper opening of the case 11 thereby placing the flange 18 on the upper end of the case 11 determining accurate positioning between the assembly 14 carrying the blades and the guard assembly carrying the perforated guard plate 38.

The negative plate 33 of the motor assembly 14 comes into firm and constant contact with the electrically conducting case 11 of the shaver by screwing the motor 14 to the upper opening of the case 11 and the spring conductor 62 comes into contact with the case 11 by screwing the bottom cap 50 to the lower opening of the case 11. Consequently, the conductive case 11 serves as the lead connecting the motor 14 with the battery 13 thereby eliminating any need for internal wiring of the shaver. In this manner, the shaver is greatly simplified both as far as assembly and subsequent maintenance is concerned and materially diminishes the troubles inherent in known devices. In addition, by providing the motor assembly 14 as a self-contained unit easily assembled with other units of the shaver, the motor can be provided as a sealed arrangement preventing waste accumulated during the shaving operation from penetrating into the moving parts of the motor, which has been known to result in improper operation or complete failure thereof.

The dry shaver in accordance with the present invention provides an especially advantageous construction consisting of only four major assemblies or parts, i.e., the tubular shell holding the perforated guard, the motor assembly including the rotating cutting blade, the lightweight nondestructive case containing the battery and serving as the conductive lead between the power supply and the motor assembly, and the bottom cap assembly containing the rotary switch. By providing each of these four assemblies as individual elements which may be easily assembled through threaded engagement, disassembly for purposes of cleaning and repair as a result of failure of one portion or another can be carried out in a relatively simple manner by people having little or no mechanical or electrical skill. In addition, the repair of the shaver is simplified as a result of the sectionalized construction since such can be accomplished by a mere exchange of broken parts. In addition, the dry shaver in accordance with the present invention is easily operated and is simple and beautiful in appearance due to the fact that the rotary switch controlling the operation of the shaver is contained in the bottom cap of the shaver and therefore does not disturb the clean outer appearance thereof.

It should also be noted that the foregoing construction provides a light weight non-destructible casing which is particularly suitable for travel purposes since dropping or subjecting the device to forceful shocks will not result in a destruction of the casing or the active elements therein as is the case with known arrangements utilizing a plastic casing, and therefore a separate protective rigid casing for the shaver is not necessary during transportation thereof.

While we have described several examples in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications Within the spirit and scope of the invention, and we therefore do not wish to be limited to the details described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. An electric dry shaver comprising, a plurality of cylindrical assemblies coupled together along a common axis by threaded engagement;

a self-contained DC. power supply having positive and negative terminals and enclosed by one of said cylindrical assemblies;

a second one of said cylindrical assemblies including a motor to be energized by said power supply and first cutting means in driven engagement with said motor;

a third one of said cylindrical assemblies adjacent said one cylindrical assembly including switch means for effecting interconnection of said motor and said power supply; and

a fourth one of said cylindrical assemblies including second stationary cutting means in contact with said first cutting means;

said one cylindrical assembly consisting of a tubular electrically conducting shell and a nonconductive sleeve secured within said tubular shell, said power supply being positioned within said nonconductive sleeve;

said third cylindrical assembly including a cylindrical cap coupled by threaded engagement with said tubular shell and contact means for electrically connecting the negative terminal of said power supply to said switch means;

said switch means including means for selectively electrically connecting said contact means to said tubular shell;

said second cylindrical assembly including a cylindrical casing coupled by threaded engagement with said tubular shell and enclosing said motor, positive and negative terminals secured to said casing and connected to said motor, said positive terminal contact ing the positive terminal of said power supply and said negative terminal contacting said tubular shell;

said cylindrical casing including an annular guide flange intermediate the ends thereof and having a diameter equal to the outer diameter of said tubular shell to accurately determine the position of said second assembly with respect to said One assembly.

2. An electric dry shaver as defined in claim 1 wherein said first cutting means includes a connecting shaft in driven engagement with said motor, a supporting plate having a plurality of arms slidingly mounted on said connecting shaft, spring means on said shaft for biasing said supporting plate in a direction away from said motor, and a substantially U-shaped elongated cutter blade mounted loosely on each of said arms of said supporting late. p 3. An electric dry shaver as defined in claim 2 wherein said fourth assembly includes a tubular body coupled by threaded engagement with the cylindrical casing of said second assembly and engaging the annular guide flange thereon to determine the accurate positioning between said second and fourth assemblies.

4. An electric dry shaver as defined in claim 3 wherein said second cutting means is in the form of a thin perforated guard plate secured across the open end of said tubular body opposite the end engaging said cylindrical casing, said cutter blades being biased into engagement with the inner surface of said guard plate by said spring means.

5. An electric dry shaver comprising, a plurality of cylindrical assemblies coupled together along a common axis by threaded engagement including,

a tubular body assembly having a perforated guard plate extending across one open thereof and a screw thread in the surface of the other open end thereof,

a motor assembly including a motor enclosed by a cylindrical casing secured to said tubular body by means of said screw thread and a rotary cutting blade in driven engagement with said motor and cooperating with said perforated guard plate to produce a shearing action;

a tubular shell assembly including a tubular shell of electrically conductive material secured to said cylindrical casing by threaded engagement and adapted to have a battery enclosed by said tubular shell and having one Side in contact with one terminal of said motor, said motor having another terminal in contact with said tubular shell;

a cylindrical cap assembly enclosing a rotary switch and secured to said tubular shell by threaded engagement, said rotary switch interconnecting said motor and said battery through said conductive tubular shell assembly.

6. An electric dry shaver as defined in claim 5 wherein the cylindrical casing of said motor assembly is provided on the outer surface thereof with a screw thread divided into two threaded portions by an annular guide flange, one threaded portion serving to engage with the screw thread in said tubular body assembly with said annular guide flange accurately determining the extent of engagement.

7. An electric dry shaver as defined in claim 6 wherein said tubular shell is provided with a threaded portion on the surface adjacent each open end thereof, one threaded portion serving to engage with the other threaded portion on said cylindrical casing with said annular guide flange accurately determining the extent of engagement.

8. An electric dry shaver as defined in claim 7 wherein said cylindrical cap includes an annular frame having a transverse web, said rotary switch including a connecting shaft extending through said transverse web, a rotary disk having a knob and a through aperture and fixed to one end of said shaft, a rotary square plate having an electrical contact segment on one side thereof and fixed on the other end of said connecting shaft, a conductive plate having spring members pressing against opposite sides of said square plate and a spring terminal in electrical contact with said conductive tubular shell, a metal plate secured to said annular frame in electrical contact with said contact segment, and a conductive helical spring in forceful contact with said metal plate and positioned to contact with the other side of said battery.

9. An electric dry shaver as defined in claim 8 wherein the face of said transverse web adjacent said rotary disk is divided into four segments, aligned with the faces of said square plate, alternate segments being provided with a common indicator visible through said through aperture.

References Cited UNITED STATES PATENTS 1,843,134 2/1932 Knippel 200-157 X 1,981,787 11/1934 Florman 30-4392 2,083,579 6/1937 Schmitt 30-432 X 2,149,995 3/1939 Gruessner 30-43.92 2,264,033 11/1941 Youhouse 3043.6 X 2,519,215 8/1950 Appleton et a1. 200-157 X 2,557,493 6/1951 Andis 200157 X 2,773,306 12/1956 Ranson 3043.92 2,867,039 1/1959 Zach 3043.6 X 3,035,191 5/1962 Kent 3043.6 X 3,043,996 7/1962 Hartwig et al 3043.6 X 3,196,299 7/1965 Kott 310-50 X 3,255,435 6/1966 Locke et al 310-47 3,283,185 11/1966 Somers et a1. 3l047 FOREIGN PATENTS 1,152,270 9/1957 France. 1,211,102 10/1959 France.

991,165 5/ 1965 Great Britain.

MYRON C. KRUSE, Primary Examiner. 

